Electric power system and control method thereof
First Claim
1. An electric power system for converting and transferring electric energy between an electric/kinetic energy conversion device and a power terminal, the electric power system comprising:
- a variable-frequency drive comprising;
a first power converter connected between a DC bus and the power terminal, wherein electric energy is transferred between the first power converter and the power terminal at a first power;
a second power converter connected between the DC bus and the electric/kinetic energy conversion device, wherein electric energy is transferred between the second power converter and the electric/kinetic energy conversion device at a second power, wherein the second power is dynamically changed in response to an operational change of the electric/kinetic energy conversion device; and
at least one energy storage module connected with the DC bus; and
a control module connected with the variable-frequency drive and the electric/kinetic energy conversion device;
wherein the control module comprises;
a spectral computing unit performing a spectral decomposition on the second power so that a spectral sequence of the second power is acquired;
a filter filtering off the spectral sequence, thereby acquiring a compensated power in a high frequency range;
a current computing unit connected with the filter, wherein according to a battery voltage of the energy storage module and the compensated power, the current computing unit calculates a reference current;
a comparing unit connected with the current computing unit, wherein by comparing the reference current with a real current of the energy storage module, the comparing unit outputs a comparing result; and
an adjusting unit connected with the comparing unit, wherein according to the comparing result, the adjusting unit controls operations of the energy storage module and adjusts the real current of the energy storage module.
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Accused Products
Abstract
An electric power system includes a variable-frequency drive and a control module. The variable-frequency drive includes a first power converter, a second power converter and at least one energy storage module. The first power converter is connected between a DC bus and a power terminal. Moreover, electric energy is transferred between the first power converter and the power terminal at a first power. The second power converter is connected between the DC bus and an electric/kinetic energy conversion device. Moreover, electric energy is transferred between the second power converter and the electric/kinetic energy conversion device at a second power. As the second power is dynamically changed, the control module controls a charge/discharge operation of the at least one energy storage module. As a consequence, the operational change of the electric/kinetic energy conversion device is reversely compensated.
14 Citations
21 Claims
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1. An electric power system for converting and transferring electric energy between an electric/kinetic energy conversion device and a power terminal, the electric power system comprising:
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a variable-frequency drive comprising; a first power converter connected between a DC bus and the power terminal, wherein electric energy is transferred between the first power converter and the power terminal at a first power; a second power converter connected between the DC bus and the electric/kinetic energy conversion device, wherein electric energy is transferred between the second power converter and the electric/kinetic energy conversion device at a second power, wherein the second power is dynamically changed in response to an operational change of the electric/kinetic energy conversion device; and at least one energy storage module connected with the DC bus; and a control module connected with the variable-frequency drive and the electric/kinetic energy conversion device; wherein the control module comprises; a spectral computing unit performing a spectral decomposition on the second power so that a spectral sequence of the second power is acquired; a filter filtering off the spectral sequence, thereby acquiring a compensated power in a high frequency range; a current computing unit connected with the filter, wherein according to a battery voltage of the energy storage module and the compensated power, the current computing unit calculates a reference current; a comparing unit connected with the current computing unit, wherein by comparing the reference current with a real current of the energy storage module, the comparing unit outputs a comparing result; and an adjusting unit connected with the comparing unit, wherein according to the comparing result, the adjusting unit controls operations of the energy storage module and adjusts the real current of the energy storage module. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A control method of an electric power system, the electric power system being connected between an electric/kinetic energy conversion device and a power terminal, the electric power system comprising a variable-frequency drive and a control module, the control module controlling a charge/discharge operation of an energy storage module of the variable-frequency drive, electric energy being transferred between the electric power system and the power terminal at a first power, electric energy being transferred between the electric power system and the electric/kinetic energy conversion device at a second power, the second power being dynamically changed in response to an operational change of the electric/kinetic energy conversion device, the control method comprising steps of:
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(a) calculating the second power according to plural parameters of the variable-frequency drive, and performing a spectral decomposition on the second power to acquire a spectral sequence of the second power; (b) filtering the spectral sequence to acquire a compensated power in a specified frequency range; and (c) the control module using the compensated power to control a charge/discharge operation of the energy storage module according to a dynamic change of the second power, thereby compensating the operational change of the electric/kinetic energy conversion device and reducing an influence of the operational change of the electric/kinetic energy conversion device on the first power. - View Dependent Claims (18, 19, 20, 21)
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Specification